Control units for dental apparatus



Sept. 11, 1956 J. E. HILL ET AL CONTROL UNITS FOR DENTAL. APPARATUS 3 Sheets-Sheet 1 Filed April 16. 1955 I INVENTORS W [3 Rob em R/ny, Jr.

Sept. 11, 1956 J HlLL ETAL 2,762,891

CONTROL UNITS FOR DENTAL APPARATUS Filed April 16, 1953 5 Sheets-Sheet 2 1/0/20 Err/e52 Roberz Rmg, dr.

INVENTORS ifimm BY ATTOR/VEKS Sept. 11, 1956 .1. E. HILL ET AL 2,762,891

CONTROL UNITS FOR DENTAL APPARATUS Filed April 16, 1953 5 Sheets-Sheet 3 /7 John [fnesf N Robe/"f R/ng, c/r.

% 6 INVENTORS d m/mm ATTORNEYS United States Patent 2,752,891 CONTROL UNITS FOR DENTAL APPARATUS John Ernest Hill and Robert Ring, Jr., Houston, Tex.

Application April 16, 1953, Serial No. 349,260 "14 Claims. (Cl. 201-48) This invention relates to new and useful improvements in control units for dental apparatus.

As is well known, the usual dental apparatus is electrically operated by a reversible electric motor and such motor is controlled both as to direction of rotation and speed by means of a rheostat. The usual control rheostat is mounted in a generally circular housing or casing which is supported upon the floor adjacent the dental chair and the rheostat is operated by foot elements or wings which extend radially outwardly from the housing. Normally and for the sake of convenience in providing an operating control on each side of the rheostat housing, two wings are mounted on the housing in diametrically opposed relationship; the foot elements or wings function to control the rheostat operation in the same manner so that it is merely a matter of choice as to which element is used. Each element or wing is adapted to be swung or moved in a horizontal plane and the direction of movement thereof controls the direction of rotation of the motor; the amount of movement, that is, the travel of the element controls the speed.

The control element or wing is actuated by the dentists foot with the toe being placed against said wing to impart movement thereto. Obviously the foot must be swung laterally using the heel as a fulcrum point to operate the rheostat, and since the control wing will return to normal center position when pressure thereagainst is released the operator must maintain a constant force against the wing so long as the motor is operated. Not only has this been found to be tiring to the operator but also maintenance of the wing in a fixed position over an extended period to hold the motor speed constant is difficult; also, when the operator is seated, as upon a stool such as dentists employ, the necessity of swinging one foot laterally to actuate the rheostat tends to disturb the operators balance and makes accurate control of the rheostat even more difficult.

It is one object of this invention to provide an improved control unit for dental apparatus wherein a depressible foot pedal is employed as the actuating element, whereby more accurate and sensitive control may be effected.

An important object of the invention is to provide a control unit for dental apparatus wherein a foot pedal upon which the foot of the operator may rest is adapted to undergo limited lateral motion to control the direction of rotation of the apparatus and is adapted to be depressed with the downward movement of the pedal controlling the speed of such rotation; said foot pedal permitting accurate and sensitive control without unduly tiring the operator.

Another object is to provide a foot pedal type of control for the usual rheostat which actuates an electric motor, said control being made in the form of an attachment whereby it is readily applicable to the usual floor rheostat control of a dental apparatus.

A further object is to provide a control unit of the character described, including a depressible foot pedal, together with a cam-like actuator which is so associated with the foot pedal that upon depression thereof a lateral movement may be imparted to the element controlling a rheostat; said cam-like element and foot pedal not only providing a simplified device but also making it possible to easily adapt the unit to any type of rheostat.

Another object is to provide a control unit of the character described wherein adjustable stops may be associated with the depressible pedal to permit adjustment of the range of the unit in any desired manner.

The construction designed to carry out the invention will be hereinafter described together with other features thereof.

The invention will be more readily understood from a reading of the following specification, and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

Figure l is a side elevation of a control unit constructed in accordance with the invention and illustrating the foot pedal in its raised position;

Figure 2 is a horizontal cross-sectional view taken on the line #2 of Figure 1;

Figure 3 is an elevation of the unit taken at a right angle to the parts as shown in Figure 1;

Figure 4 is a horizontal cross-sectional view taken on the line 44 of Figure 1;

Figure 5 is a view partly in section and partly in elevationsomewhat similar to Figure l but showing the pedal in its depressed position;

Figure 6 is a horizontal cross-sectional view taken on the line 6-6 of Figure 5;

Figure 7 is a plan view of the unit illustrating the two lateral positions of the foot pedal; and

Figure 8 is a reduced view of a modified form of the invention.

the main motor of dental apparatus (not shown). This rheostat control includes an outer generally circular housing 11 which has the rheostat (not shown) mounted therein. A central or axial control shaft 12 is disposed within the housing and radial arms 13 and 14 are secured to this shaft. As is clearly shown in Figure 4, the arms 13 and 14 are disposed diametrically opposite each other and in effect form a diametrically extending element across the upper end of the rheostat housing 11. The outer end of the arm 13 has a foot element or wing 15 secured thereto and preferably made integral therewith (Figure 1). This foot element has a wing piece 15a at its lower end which Movement of the arms 13 and 14 is restricted by upstanding arcuate flange portions 11a and 11b which are formed on the main housing 11 The rheostat as above described, having the foot elements or'wings for controlling its operation, is of standard construction and is now in general use for controllingthe operation of dental apparatus. When the wings a and 1601 are in. the position shown in Figure 4, which may be termed. a normal position, the motor controlled by the rheostat is not operating, When the wings 16a is swung laterally in one direction the rheostat'is operated to operate the motor in one direction and the amount of movement tothe wings 15a and 16a and obviouslymust' fulcrum the foot on the heel portion.

In carrying out the-present invention, a base plate 17 which is generally circular in shape overlies the upper end' of the rheostat housing 1 1 This base plate isformed with diametrically opposed arcuate flanges 18' which are adapted: to be disposed contiguous to'the upright flange members 11a and l llb (Figure 4) of the. housing 1-1 and are secured thereto by suitable screws 19. The base plate 1-7 is thus attached in its overlying-position to the rheostat housing. An upstanding boss 20which is generally rectangular in shape is preferably made integral with the base. plate and is located at one side thereof. A substantially rectangular pivot block 21 is mounted on the upper surface of the boss and is pivotally secured thereto by' a pivot bolt 22. A suitable washer or hearing 23 is disposed between the upper surface of the supportingboss 20 and the pivot block. It is evident that the pivot block is movable in a lateral plane on the axis ofv the pivot'bolt and. the lateral movement of said block is limited: by alimiting pin 24 which extends upwardly from the boss 20 and into an opening 25 formed in-the pivot block: (Figures 2 and 5). To obtain an adjustmentoftherlimit of: movement of the block with respect to the limiting pin 24, a pair of adjustable limiting screws 26 are threaded: within the sides of the pivot block 21 and have their inner ends arranged to engage the limiting pin 24. Asisclearly shown in Figure 2, the lateral movement ofthe. pivot block is restricted by the engagement of the ends of. the screws 26 with the pin 24.

Mounted upon the pivot block 21 is a foot pedal, 27 and this foot pedal is shaped to generally conform to the. sole of the foot, being preferably provided with a heel. rest 27a. The upper surface of the'pedal mayhavea rubber covering 28 or other non-skid surface. As illustrated, the foot pedal is formed with downwardly extending side flanges 29 and transversely aligned pivot lugs 30 are formed as extensions of said side flanges. The pivot lugs 30 are spaced to span the pivot block 21 and are pivotally secured to said block by a suitable pivot pin 31. The lugs 30 are disposed. nearer the heel portion of the foot pedal, and'thus the forward portion of the pedalmay move upwardly and downwardly in a vertical plane with the fulcrum being at the pivot pin 31. Since the pedal is pivotally mounted on the pivot block, it may not only undergo movement in a vertical plane but due to the mounting of the pivot block may undergo a lateral swinging movementwith the fulcrum point being on the pivot bolt 22 ofthe block 21.

Adjacent the forward-portion of the foot pedal 27 apair of transversely aligned depending ears 32 are formed, such earspreferably being integral with the side flanges 29 of: the foot pedal. Anactuator arm 33 is disposedbetween the ears 32- and is pivoted thereto by means of av pivot pin 34; Thearm 33 is formed with a lateralextension 35 (Figure 5) which underlies the foot pedal'and a stop screw 36 is mounted in the outer end of said'extension. The-stop screw 36is on one side of'thepivot pin 34' andis adapted to engage the-under surface of the. pedal; it isnormally'maintained in engagement with the foot pedal by a light spring 37 which is interposed'between the upper 4. end of the extension and the foot pedal on that side of the extension opposite the stop screw. The spring 37 functions to constantly urge the stop screw 36 into engagement with the foot pedal to maintain a predetermined relationship between the foot pedal and the arm 33.

The lower end of the actuating arm is adapted to coact with a cam actuator 38, which actuator is adapted to be secured to one of the wing pieces 15a and 16a. As shown in the drawing the cam actuator 38 is fastened to the wing piece 16a. The cam actuator comprises a body portion 39 having a slot 40 therein, and said slot is arranged to receive the wing piece 16a and to be secured thereto by suitable screws 41. The actuator also includes a pair of side extensions 42 and 43 which are generally arcuate or curved in cross-section to substantially follow the curvature of the rheostat housing 11. The side extension 42 has its upper surface curved to provide the cam surface 42a while the other extension has a similar cam surface 43a. The cam surfaces 42a and 43a merge into each other at the apex 44,which apex is disposed substantially in vertical alignment with the wing piece. In a horizontal plane the apex 44 is substantially opposite the lower end of the base plate17' and is disposed below the lower end of the actuating arm 33. The actuating arm may have a roller 33k: at its lower end to reduce the frictional contact between the arm. and'the cam surfaces 42a and 43a; also, the cam surfaces may be recessed or grooved to provide a guide way for the roller.

lt Willbe evident that when the foot pedal is moved to a position which will cause the actuating arm 33 to overlie the cam surface 42a, a subsequent depression of the foot pedal will cause the roller of the actuating arm to coact' with the inclined cam surface 42a and this will resultin a movement of the actuator block, whereby lateral movement of the wing piece which controls the rheostat is' effected. When the foot pedal is swung on the pivot block'31 to a position where the actuating arm 33 overlies the cam-surfacedda; a subsequent depression of the foot pedal will result in a movement of the actuator block and wing piece 16a in an opposite direction. Whether the actuating arm isengaged with the cam surface 42a or 43a, it' will be obvious that the distance of depression of the pedalwill control the travel or distance of movement of the working piecelfia. As has been explained, movement of 'the wing piece-in one direction will result in rotating the motorbeing controlled in one direction while the amount-"of suchmovement will control the speed. The coaction between the actuating arm 33 and the cam surfaces will result iii-controlling the direction as well as the speed; of rotation of the motor under control.

The foot pedal 27' is normally maintained in a raised position; by means of acoil spring 45 which is confined between. the base plate and the under side of the foot pedal,. the ends of the spring engaging retaining pins 46 and 47. The upward movement of the pedal by the spring 47 is limited by a stop screw 48 which is mounted atone endof the pivot block 21 (Figure 5) and which is adapted to be engagedby the under side of the foot pedal. This. screw is adjustable. to vary the limit of movement. Doumward movement of the foot pedal is limited by an elongate adjustable stop screw 49 which is threaded into: a boss 50 provided in the under side of the foot pedal. Thelower end of the screw will engage the upper surface. of thebase' plate 17' to limit the downward travel of the foot pedal.

The operation of theunit is believed obvious from the foregoing. The base plate having the pedal 27 mounted thereon is attached to the upper end of the rheostat housing 11 while the cam actuator 38 is secured to one of the wing pieces.15a or 16a. When the longitudinal axis of the foot pedal and the pivot block to which it is secured is. in. alignment with the axis of the rheostat housing, the depending actuating arm 33 is in alignment with the apex 44 of the cam actuator. The. operator places his foot upon-the pedal 27, and when. it is desired to operate the motor under control in one direction, the foot pedal is swung laterally to the position shown in dotted lines A in Figure 7. Such movement is permitted by the pivot block 21 which allows a limited swinging movement of said pivot block and pedal. This swinging of the pedal moves the lower end of the actuating arm 33 over the the cam surface 42a of the actuator and thereafter a de pression of the pedal will result in the roller 33a of the arm 33 coacting with the cam surface 42a to move the wing piece 16a in a direction to the right in Figure 3. This will cause rotation of the motor under control in one direction and by controlling the distance that the pedal is depressed, the operator may easily and accurately control the speed of rotation because continued depression of the pedal results in continued movement of the wing piece in a direction to the right.

If it is desired to operate the motor to control in a reverse direction, pressure on the foot pedal is released so that it may return to its upper position, as shown in Figure 1. The operator then swings the foot pedal to the position shown in dotted lines B in Figure 7, and this disposes the lower end of the actuating arm 33 above the cam surface 43a. Thereafter a depression of the pedal will result in moving the wing piece 16a in an opposite direction, that is, in a direction to the left in Figure 3. Of course, the distance which the pedal is depressed will control the distance that the wing piece is moved and will thereby determine the speed of the motor under control.

It is obvious that since the operator may place his foot upon the foot pedal and control the operation by merely depressing the pedal a more accurate control of the rheostat may be had. The lateral or swinging movement of the foot pedal is only a very few degrees, since it is only necessary to locate the center of the actuating arm 33 slightly to one side of the apex 44 of the cam actuator. This minimum movement makes it very easly to control the direction of rotation and from a practical standpoint, the depression of the pedal efiects the operation. The selection of direction is made by merely shifting the pedal laterally through a very small path. By providing the foot pedal type of control the operator need not constantly swing the foot in actuating the wing pieces, as is now the general practice, and the operation is much less tiring. In addition, where the operator is seated as upon a stool, there is no danger of being unbalanced by reason of having to fulcrum the foot on the heel portion thereof since the control is through depression of a pedal which actually forms a support for the foot.

In Figures 1-7, the actuating arm 33 is shown depending from the forward portion of the foot pedal with the cam actuator mounted on the wing piece 16a. However, as illustrated in Figure 8, an actuating arm 133 could be secured to the wing piece 16a while a cam actuator 138 may be secured to the foot pedal. In such case, the operation would be exactly as heretofore described.

Having described the invention, We claim:

1. A control unit for electrically operated dental apparatus including, a rheostat having a laterally movable operating element which controls operation of said dental apparatus, a depressible foot pedal adapted to be moved in a substantially vertical plane which extends longitudinally with respect to the pedal, said operating element being movable in a direction to the right or to the left from said substantially vertical plane of movement of said foot pedal, and means attached to said pedal and coacting with the operating element for imparting said right or left movement to the element upon substantially vertical depression of the pedal to thereby operate the rheostat.

2. The combination with an electrical control device having a laterally movable operating element, of a control unit including, a depressible foot pedal adapted to be moved in a substantially vertical plane which extends longitudinally with respect to the pedal, said operating 6 element being movable in a direction to the right or to the left from said substantially vertical plane of movement of said foot pedal, and means attached to the foot pedal and coacting with the operating element for imparting said right or left movement to the element when said foot pedal is substantially vertically depressed.

3. The combination with an electrical control device having a laterally movable operating element which element is normally in a predetermined position and is movable in either direction from such position, of a control unit including, a depressible foot pedal, means establishing an operative connection between the foot pedal and the operating element whereby depression of the pedal imparts lateral movement to the element, and means associated with the foot pedal for selectively controlling the direction of movement of the operating element upon depression of the foot pedal.

4. A control unit for electrically operated dental apparatus including, an electrical control device for said apparatus having a laterally movable operating element which is normally in a predetermined inactive position and which is movable in either direction from such position to control the direction of operation of the dental apparatus, a depressible foot pedal mounted for limited lateral shifting, and means establishing an operative connection between the foot pedal and the operating element whereby depression of the pedal imparts lateral movement to the element, the direction of movement of said element being controlled by the lateral position of the pedal prior to depression thereof.

5. A control unit for an electrically operated motor including, an electrical control device for said motor having a laterally movable operating element, said element having a normal inactive position and being movable in either direction from such position, movement of said element in one direction operating the motor to rotate its drive shaft in a predetermined direction with movement of the element in the opposite direction reversing the direction of rotation of the motor, a depressible foot pedal, and means attached to the pedal and coacting with the operating element for imparting lateral movement to the element when the pedal is depressed.

6. A control unit for an electrically operated motor including, an electrical control device for said motor having a laterally movable operating element, said element having a normal inactive position and being movable in either direction from such position, movement of said element in one direction operating the motor to rotate its drive shaft in a predetermined direction with movement of the element in the opposite direction reversing the direction of rotation of the motor, a depressible foot pedal, means attached to the pedal and coacting with the operating element for imparting lateral movement to the element when the pedal is depressed, and means for mounting the foot pedal for limited lateral movement, the direction of movement of the operating element when the foot pedal is depressed being controlled by the lateral position of the foot pedal prior to depression. I 7. A control unit for an electrically operated motor including, an electrical control device for said motor having a laterally movable operating element, a depressible foot pedal located above the operating element adapted to be moved in a substantially vertical plane which extends longitudinally with respect to the pedal, said operating element being movable in a direction to the right or to the left from said substantially vertical plane of movement of said foot pedal, and an actuator means between the foot pedal and the operating element coacting with the pedal and element to convert the substantially vertical downward motion of the pedal into said right or left movement of the operating element.

8. A control unit for an electrically operated motor including, an electrical control device for said motor having a laterally movable operating element, said element having a normal inactive position and being movable in either direction from such position, movement of said element in one direction operating the motor to rotate its drive shaft in. a. predetermined direction. with. move.- ment ofJthe elementzintheopposite. reversing'thedirectionv of rotation of the. motor,. a depressible" foot pedallocated: above. the operating element, means: for: mounting. the pedal for a limited. lateral. movement, and. an. actuator meansbetween the foot pedal and'operating. element coactingwith the: pedal and element to-convert the downward motion of the pedal into a lateral; movement of the operating. element, the: direction of'lateral: movement of: the operatingelement being controlled by the lateral position of the. pedal prior to. depression; thereof.

9; A control unit. for: an electrically operated motor including, an electrical control device for said motor. having a laterally movable operating. element, a depressible foot pedal located above the operating element, means for mounting. the. pedal for limited lateral movement,,an actuator. block having inclined'cam surfaces, and an actuator arm adapted to engage and coact with one or the other of. said cam surfaces, said block being secured to either the: operating element or foot pedalv with the. arm being attached to the other member, whereby when. the. pedal is depressed the actuator arm engages one. of the. cam surfaces to impart lateral movement to the; operating element.

10. A control unit assembly for attachment to the housing of the rheostat unit of a dental apparatus,- which unit: is provided. with a laterally movable operating element, said assembly comprising, a base plate adapted to be secured to the housing of a rheostat unit, a supporting member. mounted for lateral swinging movement on the plate, afoot pedal pivotally secured to the supporting member and depressible in a downward direction toward said base, and an actuator secured to the outer end of the foot pedal and depending therefrom, said actuator being adapted to coact with the operating element of the rheostat. unit to'impart a lateral movement thereto when the foot pedal is depressed.

ll. A control unit assembly for attachment to the housing of the rheostat unit of a dental apparatus, which unit is'provided' with a laterally movable operating element, said assembly comprising, a. base plate adapted to be secured to the housing of a rheostat unit, a supporting member mounted for lateral swinging movement onthe plate, a foot pedal pivotally secured to the supporting member and depressible in a downward direction toward said'base, an actuating means betweenthe foot pedal and operating means and comprising a cam actuator provided with a pair of inclined cam surfaces, said cam actuator being secured to either the foot pedal or operating elementand; functioning. when the. pedal isdepressed to, convertsthe. downward movement of the: footpedal' into. lateralzmovernent of the; operating element.

12. An assembly as set forth in claim 1th, wherein. the. supporting member on which the foot pedal; is mounted may be swungto select the directionof movement of the op erating. element.

13. A- controlunit for an electrically operated moton including; an electrical control device for said motor having a laterally movable operating element;. a dcpressible foot pedal located above the operating element, an actuator means between the foot pedal and the operating element: coacting with the pedal and" element: to convert the downward movement of. the pedal into a lateral movement of the operating element; said actuator means including an actuator block. having a pair of inciined cam surfaces, and secured to the. operating element, and an actuator arm secured. to the. foot pedal'and. adapted to engage and. co-act with the inclined cam surfaces. of the: bloclc when the foot pedal is depressed.

1.4;. A control unit for an electrically operated motor including; anelectrical control device for said motor having. a laterally movable. operating element, said element having a normal inactive position and being movable in either direction: from such position, movement of. said element inone direction operating the motor to rotate its drive shaft ina predetermined direction with movement of the element in the. opposite direction reversing the direction of rotation of the motor, a depressible foot pedal located above. the. operating. element, means for mounting the pedal: for. a. limited lateral movement, an actuator means between. the foot pedal and the operatingelement co-acting with the pedal and the element to convert the downward motion of the pedal into a lateral movement of the operating element, the direction of: the lateral movement of the operating element being controlled by the lateral position of the pedal prior to the depression. thereof, said actuator means including an actuator block having arpair of inclined cam surfaces, and secured to the operating element, and. an actuator arm securedto the foot pedal and adapted to engage and co-act with; the inclined: cam surfaces of the block when: the foot pedal is depressed.

References Cited in the file of this patent UNITED STATES PATENTS 513,213 Stanton Ian. 23, 1894 1,949,826 Chason: Mar. 6, 1934 2,460,494 Eisenberg et a1. Feb. 1, 1949 

